1. Field of the Invention
The present invention relates generally to an image retrieval system, method and an image retrieval program in which text data and/or indexes are created for retrieval from images stored in a hand-held information equipment, and more particularly to an image retrieval system, method and an image retrieval program enabling an image retrieval based on the text data and/or indexes to be effected in a hand-held information equipment having no character recognition function.
2. Description of the Related Arts
Of late years, small-sized and lightweight hand-held information equipment is widely prevailing which allows an image display on a small-sized liquid crystal display mounted thereon. Such hand-held information equipment is known from Japan Patent Laid-open Pub. No. 2000-201261 which discloses one provided integrally with an image reader. Such image reader-integrated hand-held information equipment is able to readily read and save, in the form of images, photographs, maps, articles, etc., from newspapers or magazines. In the event of a drive for example, required images of maps, guide articles, etc., of the destination may be stored in advance so that the images can readily be referred to in the course of drive to the destination. Image fetch into the hand-held information equipment may be effected by use of a memory card, an electronic mail, a facsimile, a hand-held scanner, a digital camera, etc., in lieu of the integrated image reader.
By the way, such hand-held information equipment is daily used with a multiplicity of images saved as needed. In case of searching a desired image from among a multiplicity of images, images having individual features such as scenes, persons or maps can relatively easily be retrieved since they are readily distinguishable from other images even on the small display of the hand-held information equipment. In case of documentary images, however, it is difficult to visually distinguish them from others, making it effective to retrieve them from the contents of the documents by use of a keyword. In order to retrieve the documentary images by use of the keyword, it is necessary to recognize characters from the documentary images for conversion into text data and extract words as the keyword from the text to create an index.
However, the hand-held information equipment has a lower processing performance and a restricted storage capacity as compared with the personal computer or other information processor, so that addition of the character recognition function may induce an increase in the storage capacity and therefore in costs, which may impair the advantage of its small-sized and lightweight. That is, a dictionary for recognition is needed for the character recognition, and there is a need for a multiplicity of memories to be mounted for storage of the dictionary, which results in an increase of costs.
Due to the restrained processing performance of the processor mounted in the hand-held information equipment, it is quite time consuming to extract characters from images to execute the character recognition and further to execute the index creation.